Nikon Prostaff 5 SF FFP M BDC Rifle Scopes, 3.5-14X40mm With the new BDC distance lock function that keeps everything in the first focal plane, the aiming points provided by the spot on application will be the same, regardless of what magnification the Riflescope is set at Hand-turn reticle adjustments with Spring-Loaded instant zero-reset turrets Multiple layers of anti-reflective compounds on every Glass surface provide bright, vivid sight pictures and optimum light transmission from dawn to dusk